1. Field of the Invention
The invention generally relates to sidewall image transfer processing, and, more particularly, the invention relates to improved mandrel/trim alignment in sidewall image transfer processing.
2. Description of the Related Art
Device parameters of fin-type field effect transistors (FinFETs) are extremely sensitive to semiconductor fin thickness. In order to realize the full potential of a FinFET, the silicon fin must be very thin, e.g., on the same order of thickness as that of a fully-depleted silicon-on-insulator (SOI). Similarly, line width control problems during gate electrode definition for small devices can lead to performance degradation, power consumption control issues and yield loss. Previously, lithographic techniques have been used to form device components (e.g., semiconductor fins for FinFETs, gate electrodes, etc.) in a substrate. For example, using photolithography a feature can be printed directly into a photo-resist layer and the image can be transferred into an underlying film. However, current state-of-the-art lithographic technology can not adequately and efficiently satisfy the ever-increasing demand for smaller devices and device components. Thus, the requirement for very thin, replicable, device components has re-awakened interest in sidewall image transfer (SIT) to form such components in a substrate.